GE 800D restoration

[bandersen]

My NOS flyback seems to be a dud. Had to repair two leads eaten away by corrosion. Hooked it up and heard the typical high pitched whine, but no HV. Tests good on my EICO 944, but am concerned there might be another break somewhere.

Put the old one back in and subbed a string of 1N5408 diodes for the damper. The bright line went away but it did introduce some oscillations resulting in faint vertical bands on the screen.

Have a NOS 25W4 on the way

[bandersen]

Here's some pictures.

First, 25W4 damper tube cathode. I only had one spare on hand. Both tubes produce similar results.


Here's the cathode using a string of four 1,000 volt diodes.


And the resulting screen with no signal applied showing the vertical bands from the ringing.
It's my understanding that the left side of the screen is driven by the energy recovered during the flyback period and the damper plays a big role.

[bandersen]

Took another whack at the NOS flyback and found another broken lead. Repaired that and got HV using the old 25W4. It's a bit low at 6.7 kV and there's some faint striping, but no bright vertical line!


I also unmounted the focus coil so the 5AXP4 could auto-focus properly.
Tweaked all the controls and got a very respectable image
Finally a light at the end of the tunnel for this project!
I've not given up on the original flyback quite yet. It tests good on an EICO 944.
I'll tinker around wit it more when the NOS damper tube gets here in a few days.

[bandersen]

I'm giving up on the old flyback. Tried everything I could think of and nothing had any effect on the left side distortion.

Life's too short - time to move on. I cleaned out the HV cage, wired in a new HV lead and installed a Stancor A-8130.



Next I'll install the full size CRT and go through all the adjustments.

[bandersen]

Reinstall the 10BP4 and adjusted the ion trap magnet and focus coil. Glad I took some reference photos

Yoke needs a tweak as do the height and linearity, but it's looking good.
No need for an alignment. Sharp enough to see chroma dots.


Now on to bakelite polishing.


I see the former owner burned his name into cabinet under the controls.


Or is it the service tech that worked on it? Matches the stamp on the chassis.

[Tom9589]

I Googled the address. It's definitely a residence, not a TV repair shop.

[Eric H]

Lots of info on Mr Oehme online.
I bet he stamped his name on it in case it was stolen.

https://www.ancestry.com/1940-census...k-Oehme_56cfbh

[bandersen]

Thanks for the link. I'll have to ask the owner where he got the set. Maybe from a relative of Mr Oehme ?

Did a test fitting last night and let it run a while. Bit of hum in the sound but otherwise no problems. Will try to tweak the sounds alignment.


Still have the rest of the cabinet to clean up. Quite a difference

[bandersen]

Mr Oehme wasn't taking any chances and carved his name into the back as well.


Almost done Well worth it though as this is one of the nicest pieces of bakelite I've comes across.
If it wasn't for the owners intentional scratches, it'd be nearly flawless.

[TV-collector]

Originally Posted by bandersen

Mr Oehme wasn't taking any chances and carved his name into the back as well.

Almost done Well worth it though as this is one of the nicest pieces of bakelite I've comes across.
If it wasn't for the owners intentional scratches, it'd be nearly flawless.

Question regarding the photo:
I own the same set, and if you look into the cabinet, you can see that the grill
inside is pasted, maybe asbestos???????????
Thanks,

TV-collector

[bandersen]

No, it's not asbestos. It's a metal mesh flocked with a redish brown material. I assume to match the cabinet. It's just there to stop stuff from falling in to the cabinet through the vent slots.

[bandersen]

Months later and I'm still poking around with this set. I was able to almost completely eliminate the ringing on the left by swapping through a few 19BG6s.

I then realized I had way too much width and height as this set has a rectangular mask. A few hours of playing with all the adjustments resulted in a smaller raster with pretty good linearity.

Then I finished polishing the cabinet and cleaning the knobs.
Hands down the most frustrating set I've worked on, but it's finally done.

[AlanInSitges]

...and what a looker! Really nice work.

[old_tv_nut]

Museum grade, I'd say!

[Kevin Kuehn]

That set turned out great. It's very interesting how the left side shading bands turned out to be horizontal output tube sensitive. I guess one can't have too many shopping bags full of HO tubes available to try.